A conventional vacuum cleaner may be used for a housekeeping in a house or in a hospital for sucking dusts accumulated on the floor, carpet, and furniture for an interior cleaning purpose. In a hospital, a sterilized environment without bacteria, fungi or hazardous dusts should be maintained so that sterilizing agents or chemicals are required to be sprayed in the hospital, which however may cause dislike chemical odors or even harmful to the patients or persons staying in the hospital. Even ultraviolet lamps may be installed in the interior of a hospital, such a fixed ultraviolet lamp has a fixed or limited light projecting direction or angle, unable to have a wide scope sterilizing effect in a hospital. Meanwhile, the ultraviolet ray will damage human skin cells when emitted from such a fixed ultraviolet lamp.